The present invention relates to a headrest assembly for protecting the neck of a vehicle seat occupant by preventing a sudden movement of the head of the occupant upon rear end collisions
Typically, a motor vehicle is provided with a headrest arranged on the upper part of a seatback in order to protect the neck of a vehicle seat occupant in case of rear end collisions and to be comfortable in normal driving by supporting the seat occupant""s head.
The accompanying FIG. 1 is a side view depicting the state of a vehicle seat occupant in general when a rear end collision is occurred. As shown, a headrest 13 is mounted on the upper part of a seatback so as to support the head of an occupant. In this arrangement, because the rearward movement of a head is restricted while forward movement of the head is free, the vehicle seat occupant risks a serious neck injury by a rear impact such as rear end collisions. Namely, on rear end collision, the head and the body of the occupant are backwardly moved in a different acceleration by an inertial force, whereby a neck injury can occur due to the sudden movement of the head with respect to the body.
In consideration of said drawback, the Korean Utility Model Application No. 1996-033940 discloses a headrest assembly for protecting the neck, which is designed to rapidly move the headrest toward the head of a vehicle seat occupant upon a rear end collision in order to restrict the rearward movement of the head of the occupant. As described in this Utility Model application, an actuating rod is positioned in a seatback for moving the headrest forward in order to support the rearward movement of the head of an occupant. A post-insert hole formed on the upper end of said actuating rod secures a post extending from the headrest, wherein said actuating rod is downwardly extended to the part where the load of the occupant is applied. The actuating rod is also pivotally mounted to the cross member of a seatback frame by means of a pivotal ring, whereby on rear end collisions, the upper part of said actuating rod is rotated forward at a certain angle and the lower part of said actuating rod is rotated backward at a certain angle.
However, such headrest assemblies have disadvantages. As shown in FIG. 5, a rear impact such as rear end collisions causes the back of the occupant to push the seatback 11 in backward direction, which accordingly causes the lower end of the actuating rod 15 (hereinafter, which is referred as to press part M to be pushed backward. In FIG. 5, a letter xe2x80x98Kxe2x80x99 refers to the distance from the pivotal ring 19 to the center of the headrest 13, and the letter xe2x80x98axe2x80x99 refers to the distance from said pivotal ring 19 to the center of the press part M.
In the above headrest assembly, the movement of the press part M is very slight because the seatback 11 has characteristic shock absorption in itself, moreover the actual rotating angle of the actuating rod 15 is not sufficient. Accordingly, the headrest 13 cannot be sufficiently moved toward the head of the occupant. Furthermore, the headrest is unnecessarily moved forward in response to the ordinary movement of the occupant.
The present invention provides a headrest assembly for protecting the neck of a vehicle seat occupant that enables the headrest to sufficiently move forward to support the head of the occupant. The movement of the headrest is initiated by a inertial force occurred through rear end collisions.
According to a preferred embodiment, the present invention includes a guide body, a first actuating rod, a second actuating rod and a press part disposed within a vehicle seat including a headrest. The guide body has a guide groove formed in a vertical direction.
Upon a rear end collision, the lower end of the second actuating rod is moved backward and the upper end of said second actuating rod is moved forward. Subsequently, the first actuating rod linked to the second actuating rod is moved forward while the sliding end of the second actuating rod is sliding through the guide groove of the guide body.
The first actuating rod is integrally formed with the guide body, which is pivotally connected to the upper cross member of the seatback frame and rotatably installed inside the seatback. The headrest is mounted on the upper end of the first actuating rod, and is moved forward upon rear end collisions in order to support the head of a vehicle seat occupant. The second actuating rod is pivotally connected to the lower cross member of the seatback frame under the first actuating rod 21. The second actuating rod is linked to the first actuating rod by means of a sliding end engaged with the guide groove. The press part is formed at the lower end of the second actuating rod such that a rearward load from the back of the seat occupant may be applied thereto.
In a further preferred embodiment, a resilient means is installed in front of the press part which is deformed to change the thickness thereof under the pressure and restored to an original thickness thereof when the pressured is released. Furthermore, the resilient means is preferably an airbag filled with a predetermined amount of air, and made of an elastic material.
In a further preferred embodiment of the invention, the headrest assembly includes at least one headrest support member pivotably mounted on a first horizontal axis with respect to the seat back and extending above the seat back. The headrest is mounted on the at least one headrest support member opposite the pivotable mount. An actuating member is pivotably mounted on a second horizontal axis disposed below the first horizontal axis. The actuating member includes an actuating arm extending below the second horizontal axis to receive forces applied by a seat occupant as a result of a rear end collision, and a linkage arm extending above the second horizontal axis. The linkage arm is slidably linked to the at least one headrest support member and cooperates with the support member to force the headrest forward in response to rearward force applied to the actuating arm by the vehicle seat occupant.